Opening a walkthrough when another walkthrough is open should reuse the same tab

[eamodio]

It seems odd to me that opening a walkthrough while another one is opened, opens another tab. I had expected it to replace the current one.

This leads to an undesirable case if one walkthrough has a link/step that leads to another walkthrough.

/cc @JacksonKearl @digitarald

[JacksonKearl]

It's by design that more than one can be open at the same time, though I could theoretically see having it replace if the second was opened via a link in the first. How are you opening it?

[eamodio]

I have a step that has a button in the description to open another walkthrough.

[JacksonKearl]

Duplicate of #129735